More than 136,000 Houston-area homes flooded in the aftermath of Hurricane Harvey?s landfall on August 25, 2017. The greater Houston area experienced record-breaking rain over the subsequent four days, with more than 60 inches of rain measured in several areas?a record in the U.S.17 The hurricane overwhelmed numerous sewage treatment centers, caused damage and probable contamination from at least 13 Superfund sites, triggered unscheduled air emissions from emergency shut-down and start-up procedures at area refineries, and overwhelmed several flood retention reservoirs leading to up to two weeks of high water in some neighborhoods. The full health impact is poorly understood but 75 deaths, from during the event or over the subsequent weeks, were attributed to Hurricane Harvey.15 Respiratory symptoms and rashes were commonly reported in several surveys conducted by Baylor College of Medicine within the first 30 days of the event.6 Much of this mortality and morbidity could have been reduced by better public health planning,1,41,42 which is in turn dependent on strong health data5,10,26,44 to inform policy development. When Harvey made landfall, our group?the Baylor College of Medicine Environmental Health Service?was conducting a pragmatic randomized clinical trial, the ?Houston Home-Based Integrated Intervention Targeting Better Asthma Control (HIITBAC) for African Americans.?14 As part of this study, we collected extensive data on environmental hazards in patient homes, as well as clinical and healthcare utilization data. We also banked blood specimens. Our proposed study will focus on a subgroup of the parent HIITBAC cohort, which we refer to as HIITBAC1 for this application. From HIITBAC1, we will enroll from 108 individuals who exited the study in the 12 months preceding Harvey; this Hurricane Harvey subset is referred to as HIITBAC2-HH. We will use the comprehensive HIITBAC1 exit visit data as the baseline for the proposed study. The proposed HIITBAC2-HH follow-up protocol will include the original HIITBAC1 assessments, as well as additional Harvey-driven questionnaires and environmental and biological samples (including exhaled nitric oxide, airborne mold samples, and a post-Harvey blood sample), at approximately 6 months post-Harvey. We will also conduct a follow-up phone assessment of asthma control, resilience and posttraumatic stress at approximately 18 months after Hurricane Harvey. In addition to our evaluation and analysis of this follow-up cohort, we will examine, for selected outcome measures, the complete HIITBAC1 dataset on whom we have pre- and post- Harvey data. This will add additional longitudinal and post-Harvey data points to enrich aspects of the proposed study. Our ongoing and very active HIITBAC1 Patient / Stakeholder Advisory Board will advise the study team on study implementation, participant retention, and dissemination. Taking advantage of our existing cohort of high-risk asthmatics in the context of Hurricane Harvey, we hope to add valuable information to current discourse on the public health ramifications associated with disasters.